Systematic investigation of SO2 adsorption and desorption by porous powdered activated coke: Interaction between adsorption temperature and desorption energy consumption

Porous carbon materials have been widely used for the removal of SO₂ from flue gas. The main objective of this work is to clarify the effects of adsorption temperature on SO₂ adsorption and desorption energy consumption. Coal-based porous powdered activated coke (PPAC) prepared in the drop-tube reactor was used in this study. The N₂ adsorption measurements and Fourier transform infrared spectrometer analysis show that PPAC exhibits a developed pore structure and rich functional groups. The experimental results show that with a decrease in adsorption temperature in the range of 50–150?℃, the adsorption capacity of SO₂ increases linearly; meanwhile, the adsorption capacity of H₂O increases, resulting in the increase in desorption energy consumption per unit mass of adsorbent. The processes of SO₂ and H₂O desorption were determined by the temperature-programmed desorption test, and the desorption energies for each species were calculated. Considering the energy consumption per unit of desorption and the total amount of adsorbent, the optimal adsorption temperature yielding the minimum total energy consumption of regeneration is calculated. This study systematically demonstrates the effect of adsorption temperature on the adsorption–desorption process, providing a basis for energy saving and emission reduction in desulfurization system design.